Strain relief clamp

ABSTRACT

A strain relief clamp for a wire bundle which may be disposed at an angle to the axis of a mating connector including a cylindrical collar for connection to the mating connector, a wire guide having a tubular portion located concentrically within the cylindrical collar and secured to the collar by a snap ring within aligned circumferential grooves in each, and an arm portion joined to the tubular portion and extending outwardly at an angle to the axis of the guide, the wire guide being rotatable to a position where the arm portion is aligned with the wire bundle prior to or after the collar has been loosely connected to the mating connector whereupon the guide may be non-rotatably locked relative to the mating connector and a bundle binder attaches the wire bundle to the arm portion.

United States Patent [1 1 [111 3,732,527 McKnight 1 May 8, 1973 [54]STRAIN RELIEF CLAMP 3,603,913 9/1971 Hasty, Jr. ..339 104 [76] Inventor:Thomas L. McKnight, Lake San Marcos, Cam Primary Examiner-Richard E.Moore Att0rney-Paul Adams [22] Filed: May 4,1971

Appl. No.: 140,091

Related 0.8. Application Data [5 7] ABSTRACT A strain relief clamp for awire bundle which may be disposed at an angle to the axis of a matingconnector including a cylindrical collar for connection to the matingconnector, a wire guide having a tubular portion located concentricallywithin the cylindrical collar and secured to the collar by a snap ringwithin aligned circumferential grooves in each,v and an arm portionjoined to the tubular portion and extending outwardly at an angle to theaxis of the guide, the wire guide being rotatable to a position wherethe arm portion is aligned with the wire bundle prior to or after thecollar has been loosely connected to the mating connector whereupon theguide may be non-rotatably locked relative to the mating connector and abundle binder attaches the wire bundle to the arm portion.

5 Claims, 9 Drawing Figures 1 STRAIN RELIEF CLAMP RELATED APPLICATIONBACKGROUND OF THE INVENTION This invention relates to clamps for wirebundles and more particularly to a strain relief clamp for a wire bundlewhich permits the arm thereof to be rotated in alignment with the wirebundle prior to or after the clamp has been connected to a matingconnector.

In most applications of wire bundles in vehicles, notably aircraft, thebundles are subjected to flexing, pulling and movement in general due'tothe flexing of the structure of the aircraft itself. In suchapplications, the individual wires of the wire bundle are connected toother wires on the opposite side of a wall or bulkhead by means of aconnector assembly which is inserted through an opening in the wall. Theconnector assembly contains a multiplicity of pin plugs and each wire ofthe bundle is connected to an individual wire pin for insertion into acorresponding pin plug. Because of the pulling on the wire bundle fromthe flexing of the aircraft, and the vibration of the bundle, a strainrelief clamp may be provided. Such a clamp is attached to the wirebundle and to the connector assembly to maintain the bundle of wiressecure in the presence of vibration and to reduce the possibility ofpulling on the individual wire pins to which they are soldered orotherwise attached.

The existing strain relieving clamp design has several disadvantages.One such disadvantage is that the arm of the clamp rotates as the clampis being connected to the connector assembly and once, the clamp istight, the

arm thereof extends outwardly in a direction which,

usually does not correspond to the direction that the wire bundle entersor leaves the connector. The clamp must then be loosened to bring thearm into alignment with the wire bundle or the wire bundle must be movedto an aligned position with the arm. It is therefore a primary object ofthis invention to provide a strain relief clamp for a wire bundle with awire guide means which is rotatable relative to the collar after thecollar is secured to a mating connector enabling the wire guide means tobe aligned with the wire bundle for attachment thereof.

It is a further object of this invention to provide a strain reliefclamp for use with a wire bundle which has a collar for connection to amating connector and a wire guide means including a tubular portion andan arm portion which is independently rotatable prior to or after thecollar is connected, to align the arm portion with the wire bundle forattachment thereto.

It is an advantage of the strain relief clamp according to thisinvention that the wire guidemeans thereof may be rotated to anyposition prior to or after the collar is loosely secured to a matingconnector.

It is a further advantage of such a clamp that the bundle of wires neednot be moved in order to attach the bundle to the wire guide means ofthe clamp.

It is yet a further advantage of one embodiment of such a clamp that theangle of approach of the wire bundle to the connector can be rotatedwithout loosening the collar thereof from the mating connector.

It is yet a further advantage of such embodiment of the clamp thatlocking means can be selectively released enabling the angle of theapproach of the bundle to be changed without releasing the collarconnection to the mating connector.

It is another advantage of such a strain relief clamp that it isprovided with a releasable locking means to lock the collar and the wireguide means together enabling the wire guide to help maintain the bundleof wires in the desired position.

SUMMARY OF THE INVENTION A strain relief clamp according to the presentinvention including a generally cylindrical collar for connecting to amating connector and a wire guide means rotatably secured to the collarand to which is secured a wire bundle which may approach the connectorat an angle to the axis thereof. The strain relief clamp also ineludesreleasable locking means to non-rotatably lock the wire guide meansrelative to the mating connector. In the preferred embodiment, the wireguide means includes a tubular portion concentrically rotatably mountedwithin the collar and an arm portion attached to the tubular portion andextending outwardly therefrom. The collar may have threads for screwingonto a mating connector and prior to or after the collar is looselythreaded on the mating connector, the arm portion is rotated into analigned position with the wire bundle and the wire bundle is secured tothe arm portion by a binder strap. The wire guide means is then lockedwith respect to the mating connector by suitable means such as theengaging edges of the connector and tubular portion which mayfrictionally prevent rotation (or the edges may be sawtoothed andinterlocking), 0r splines may be provided on the connector and tubularportion, or a set screw may be mounted in the collar for engaging thetubular portion so as to non-rotatably lock the guide means relative tothe mating connector.

These and various other objects and advantages of the strain reliefclamp according to this invention will become apparent to those skilledin the art from consideration of the following detailed description anddrawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation view of awall to which a conventional wall connector assembly with an exemplaryembodiment of a strain relief clamp according to this invention ismounted;

FIG. 2 is an enlarged side elevation view of the strain relief clamp ofFIG. 1 with a section thereof partially cut away to show the internalconstruction of the clamp.

FIG. 3 is an end view of the strain relief clamp of FIG. 1;

FIG. 4 is a bottom view of the strain relief clamp of FIG. 1;

FIG. 5 is a side elevation view of the strain relief clamp of FIG. 1with a modified guide cylinder portion;

FIG. 6 is a side elevation view of a modified strain relief clarnp witha section thereof partially cut away;

FIG. 7 is a view of the clamp shown in FIG. 6 taken along the lineVII-VII;

FIG. 8 is a side elevation view of a second modified strain relief clampwith a section thereof partially cut away; and

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTIONReferring now to the drawings and particularly FIG. 1, the exemplaryembodiment of a strain relief clamp in accordance with the presentinvention is illustrated in connection with a conventional wall mountedconductor assembly indicated generally at 10. Assembly is secured in amanner well known in the art through an opening in a wall 1 1 such aswould be found in vehicles, for example, an aircraft. The wall mountedconnector assembly 10 provides a coupling or connection for eachindividual wire of a wire bundle 12, oriented with respect to theconnector assembly 10 at a position other than along the axis thereof.As shown in FIG. 1, the wire bundle l2 approaches the connector assembly10 from a direction generally at a right angle to the axis thereof.

The wall connector assembly 10 includes an exemplary embodiment of astrain relief clamp according to this invention. The strain relief clamp15 generally includes a ring or cylindrical collar, indicated generallyat 20, wire guide means, indicated generally at 30, means securing thecollar and the wire guide means 30 together for relative rotationtherebetween, indicated generally at 35, and means for attaching,positioning or holding the wire bundle 12 to the wire guide means 30,indicated generally at 40. The clamp 15 also includes releasable lockingmeans, indicated generally at 45, to lock the collar 20 and the wireguide means 31) against relative rotation therebetween, and thus lockmeans 30 relative to the connector.

The ring or cylindrical collar 20 of the exemplary embodiment of thestrain relief clamp 15 as best seen in FIG. 2 is generally tubular inshape and may be either male or female depending upon the particularconnector assembly 10 with which it is to be used. In the exemplaryembodiment, a female collar is shown, having connecting means, indicatedgenerally at 21, at the left end thereof for connecting to a matingconnector, not shown. The particular connecting means 21 shown is aninternal thread 22 for mating to an external thread (not shown). It willbe appreciated that other connecting means such as J-slots or the likemay be employed with collar 20 for effecting the connection.

Externally, the collar 20 has a neck 23 inserted into the matingconnector and torque means 24 for applying rotative torque to the collar20, such means in the exemplary embodiment comprising a knurled surface25.

The wire guide means 30 in the exemplary embodiment of the strain reliefclamp 15 includes a tubular portion 31 with an external diameter lessthan the internal diameter of the collar 20 and an internal diametergreater than the diameter of the wire bundle 12. The tubular portion hasan arm portion 32 associated therewith which is joined at its upper endto the tubular portion 31 as an integral part thereof. The arm portion32 extends outwardly from the tubular portion 31 radially; or may extendat an angle to the axis thereof which corresponds to the angle that thewire bundle 12 approaches the wall connector assembly 10 which in theexemplary embodiment is at a right angle thereto.

As best seen in FIG. 4, the arm portion 32 is of a curved cross sectionso as to more readily receive the wire bundle 12. As best seen in FIG.3, the arm portion 32 is slightly tapered from the tubular portion 31towards the outward end and terminating in an arcuate member 33 forengaging and holding the wire bundle l2. ,1

As best seen in FIGS. 3 and 4, the wire guide means 30 is inserted intothe collar 20 with the tubular portion 31 positioned concentricallytherein. The collar 20 and the wire guide means 30 are secured togetherby securing means indicated generally at 35 which prevents relativeaxial movement while permitting relative rotation of the collar 20 andthe wire guide means 30. In the exemplary embodiment, the securing means35 includes an internal circumferential groove 36 in the collar 20adjacent the right hand end thereof, and a corresponding externalcircumferential groove 37 centrally located in the tubular portion 31.The groove 36 opens inwardly toward the axis of the collar, and thegroove 37 opens outwardly so that when the grooves 36 and 37 arealigned, an opening is formed for a ring 38 such as a snap ring. Thering 38 seats in both grooves to maintain the grooves in axial alignmentwhile permitting rotation of the wire guide means 30 relative to thecollar 20.

Once the strain relief clamp 15 has been assembled, the wire bundle 12is inserted through the tubular portion 31 of the wire guide means 30and the pins (not shown) containing the ends of the individual wires areinserted into a corresponding pin plug in the wall connector assembly10. The strain relief clamp 15 is next secured to the wall connectorassembly 10 by the collar 20 being partly screwed onto the connectorassembly 10. After the collar 20 is on, the wire guide means 30 isrotated until the arm portion 32 is aligned with the wire bundle 12 sothat the wire bundle 12 rests against the arm portion 32 and the arcuatemember 33. The wire guide means 31) rotates relative to the collar 20 bysliding with and/or along the ring 38.

Once the arm portion 32 and the wire bundle 12 are aligned, means 40 forholding or positioning the arm portion 32 to the wire bundle 12 issecured. In the exemplary embodiment the means 41) includes aconventional non-conducting wire bundle binder 41 which encircles boththe wire bundle 12 and the outer end of the arm portion 32 to seat in anotch 42 adjacent the outer end of the arm portion 32. The notch 42prevents the binder 41 from being pulled off the outer end of the armportion 32.

Once the wire bundle 12 and the arm portion 32 are secured together, thewire guide means 30 is locked to the collar 20 by releasable lockingmeans 45. The locking means may comprise the end faces of the tubularportion 31 and the end face of the connector (not shown) which axiallyabuts the tubular portion 31. Where collar 20 threadably engages themating connector, collar 20 when tightened will force the ends intotight contact so that they will be frictionally interlocked. Wheresevere vibration is encountered however, other locking means arepreferred such as that shown in the first exemplary embodiment whichincludes a tapped hole 46 through the collar 20 to the interior thereof,and a set screw 47 screwed into the tapped hole 46. The inner end of theset screw 47 engages the tubular portion 31 of the wire guide means 30to lock the wire guide means 30 to the collar 20 so that the weight ofthe wire bundle 12 or the vibration of the environment will not rotatethe wire guide means 30 out of its proper position. The tubular portion31 may be provided with axially extending striations 48 on its exteriorsurfaces for contact with the end of the set screw to aid in locking, asillustrated in FIG. 5. Also, locking of the wire guide means 30 and thecollar 20 relative to one another enables the wire bundle 12 via the armportion 32 to hinder any tendency of the collar 20 to unscrew because ofvibration, etc. It will be understood that other locking means, forexample, end serrations of the wire guide means and on the matingconnector to which collar 20 is secured, as shown in FIGS. 6 and 7, maybe provided. In the latter example the wire guide means is not lockedrelative to the collar but is locked directly to the connector assembly,since the teeth 51 on the tubular portion 31 mesh with the teeth 52 onthe mating connector body 53. Another alternative locking means is shownin FIGS. 8 and 9 wherein the tubular portion 31 is provided with axialslots 55 and the mating connector body 53 carries mating splines 56. Thestrain relief clamp securely holds the wire bundle 12 so as to transferany pull on the bundle 12 to the connector assembly rather than havingsuch pull applied to the individual wires at the pins.

Thus the strain relief clamp 15 according to this invention for a wirebundle l2 permits the wire guide means 30 to rotate relative to thesecured collar to any position to be aligned with the wire bundle 12 forsecuring the wire bundle 12 to the strain relief clamp 15.

The foregoing description of the exemplary embodiment of the strainrelief clamp of this invention is intended to be exemplary only and itshould be understood that other modifications or alterations of theconstruction and method of assembly of the clamp may be made and arewithin the scope of the present invention which is defined and limitedonly by the following claims.

I claim:

1. A strain relief clamp for a wire bundle, the clamp adapted to beattached to an electrical connector, comprising:

a generally cylindrical collar including means for attaching said collarto the connector;

wire guide means including a tubular portion positioned concentricallywithin the collar for receiving the wire bundle and having an armextending away from said tubular portion from one edge thereof, said armtapering toward the outer end and terminating in a transverse member,said arm having a notch adjacent the outer end thereof; means securingthe collar and the tubular portion of the wire guide means together,said securing means preventing relative axial movement while permittingrelative rotation between said collar and said wire guide means;

releasable locking means to non-rotatably lock said tubular portion ofsaid wire guide means relative to the connector; and

a wire bundle binder encircling the wire bundle and said arm and seatedin said notch.

2. The clamp of claim 1 wherein said releasable lockin means comprises ascrew threadably mounted 1n sat collar for selective engagement withsaid tubular portion of said wire guide means, whereby when said collaris non-rotatably attached to said connector, said screw may be made toengage said tubular portion of said wire guide means so that said arm isnon-rotatably locked to said connector.

3. The clamp of claim 2 wherein said tubular portion of said wire guidemeans includes axially directed striations on the outer surface thereofto be engaged by the end of said screw to aid in locking said wire guidemeans relative to said collar.

4. The strain relief clamp of claim 7 adapted to be attached to aconnector having a threaded cylindrical body with a serrated end wall,said means for connecting said collar to said connector comprisingthreads, said tubular portion having a diameter approximately equal tothe diameter of the connector body and said releasable locking meanscomprising a serrated end wall for engagement with said connector bodyserrated and wall, whereby said collar may be initially threadablyattached to the electrical connector so that said arm is free to berotated to a desired position and said collar subsequently tightened onthe electrical connector to efiect mating engagement of said serrationson said connector body and said tubular portion of said wire guide meansto non-rotatably lock the arm relative to the connector.

5. The strain relief clamp of claim 1 adapted to be attached to aconnector having a threaded cylindrical body, said means for connectingsaid collar to said connector comprising threads, said tubular portionhaving a diameter approximately equal to the diameter of the connectorbody, and said releasable locking means comprising axial splines on theexterior surface of said connector cylindrical body and axial slots onsaid tubular portion of said wire guide means, whereby said collar maybe initially threadably attached to the electrical connector so thatsaid arm is free to be rotated to a desired position and said collarsubsequently tightened on the electrical connector to effect matingengagement of said splines on said connector body with said slot on saidtubular portion of said wire guide means to non-rotatably lock the armrelative to the connector.

' Q'NITEED STATES" fAT E NToFFICE ,CERT F QATE...QF..-QQRR T g Pater 1tNo. {3 ,732,5g1' Dated Mav a. 1973 i j Iiwefit r I Thomas L. McKnight Itis certified that error appears in the aboveidentified patent and thatsaid Letters Patent 15 hereby corrected as shown below: i

* calumno, Line 23, should read 1 '.S ijg'ned and sealed this 10th dayof September 1974.

(SEAL) Att'e'st:

MCCOY M. GIBSON, JR. c. MARSHALL DANN Attesting Office-r a vCommissioner of Patents

1. A strain relief clamp for a wire bundle, the clamp adapted to beattached to an electrical connector, comprising: a generally cylindricalcollar including means for attaching said collar to the connector; wireguide means including a tubular portion positioned concentrically withinthe collar for receiving the wire bundle and having an arm extendingaway from said tubular portion from one edge thereof, said arm taperingtoward the outer end and terminating in a transverse member, said armhaving a notch adjacent the outer end thereof; means securing the collarand the tubular portion of the wire guide means together, said securingmeans preventing relative axial movement while permitting relativerotation between said collar and said wire guide means; releasablelocking means to non-rotatably lock said tubular portion of said wireguide means relative to the connector; and a wire bundle binderencircling the wire bundle and said arm and seated in said notch.
 2. Theclamp of claim 1 wherein said releasable locking means comprises a screwthreadably mounted in said collar for selective engagement with saidtubular portion of said wire guide means, whereby when said collar isnon-rotatably attached to said connector, said screw may be made toengage said tubular portion of said wire guide means so that said arm isnon-rotatably locked to said connector.
 3. The clamp of claim 2 whereinsaid tubular portion of said wire guide means includes axially directedstriations on the outer surface thereof to be engaged by the end of saidscrew to aid in locking said wire guide means relative to said collar.4. The strain relief clamp of claim 7 adapted to be attached to aconnector having a threaded cylindrical body with a serrated end wall,said means for connecting said collar to said connector comprisingthreads, said tubular portion having a diameter approximately equal tothe diameter of the connector body and said releasable locking meanscomprising a serrated end wall for engagement with said connector bodyserrated and wall, whereby said collar may be initially threadablyattached to the electrical connector so that said arm is free to berotated to a desired position and said collar subsequently tightened onthe electrical connector to effect mating engagement of said serrationson said connector body and said tubular portion of said wire guide meansto non-rotatably lock the arm relative to the connector.
 5. The strainrelief clamp of claim 1 adapted to be attached to a connector having athreaded cylindrical body, said means for connecting said collar to saidconnector comprising threads, said tubular portion having a diameterapproximately equal to the diameter of the connector body, and saidreleasable locking means comprising axial splines on the exteriorsurface of said connector cylindrical body and axial slots on saidtubular portion of said wire guide means, whereby said collar may beinitially threadably attached to the electrical connector so that saidarm is free to be rotated to a desired position and said collarsubsequently tightened on the electrical connector to effect matingengagement of said splines on said connector body with said slot on saidtubular portion of said wire guide means to non-rotatably lock the armrelative to the connector.